From: gtosiris{at}mpx.com.au
To: atm{at}shore.net
Reply-To: gtosiris{at}mpx.com.au


On 29 Dec 2002, at 22:00, Doug Tanaka wrote:

>
> At 03:47 PM 12/29/2002, you wrote:
>
>
> >("atm{at}shore.net")
> >
> >        Hello all , I have recently bought a respirator from Lowes
> > hardware for use in cutting thick
> >plate glass. I have done this before but I needed to get a better
> >respirator.
> >      The respirator is AOSafety brand and has the two round
> >      cylindrical
> > canisters on each side
> >that can be replaced when  they are spent.  I have looked on the
> >labels and info provided with the respirator but it says nothing
> >about glass particles.
> >        It list the following applications......Paint &
> > Pesticide....Solvent & Glue,..Thinner....Dusts & Mists...
> >I would assume this respirator would be good enough to use in cutting
> > plate glass while keeping the cut wet and shielded?? Any comments I
> >know that glass dust is a very dangerous thing. I have heard all the
> >warnings and respect them.                      RUSS JOCO
>
> Russ,
>
> If you keep the cut wet and wear the mask you should be OK.  However,
> if there is any dust and you have a beard, dust can creep between the
> respirator and your beard.  I have a beard and do a lot of woodworking
> so I use a Racal respirator - a helmet and face shield connected by a
> hose to a battery powered forced air filter worn around the waist.
> The filtered air is forced through the tube and into the helmet space
> creating positive air pressure.  It is rather expensive but does a
> fine job of supplying clean air (and I don't have to shave ;-).  BTW,
> the filters that came with you respirator sound like organic vapor
> filters.  They will work fine but if you only need to filter particles
> you might consider getting cartridges that only filter dust, since
> they're cheaper, and save the organic vapor cartridges in case you
> need it for spray paint, etc.

Hi. The cartridges are identifiable as combined dust and gas cartridges.
That is they will be a "two-layer" combination of charcoal and
and fibrous material. The charcoal is also good for low levels of acid
gases/vapours, and the fibrous material is also good for mists (liquid
droplets). The fibrous material for any of these respirators has an
electrostatic charge to aid capture of particules. Any oil mist will simply
"kill" the electrostatic charge and make the respirators some 40
percent less effective. Once any gas/vapour respirator is removed from the
sealed wrapping paper it will start to sorb water vapour from the air but
its use in a gas/vapour environment will normally mean that the captured
water vapour is replaced by such. The issue for organic vapour respirators
regarding partial use is diffusion. Over time the gas/vapour captured will
diffuse over all the unused (unsorbed) charcoal. Regards, Gary Thompson

--- BBBS/NT v4.00 MP